Machine for leveling land and forming borders



April 4, 1939. J. J. ALLISON ET AL 3,

MACHINE FOR LEVELING LAND AND FORMING BORDERS Filed April 20, 1938 3 Sheets-Sheet 1 April 4, 1939.

J. J. ALLISON ET AL 2,153,446

MACHINE FOR LEVELING LAND AND FORMING BORDERS Filed April 20, 1938 5 Sheets-Sheet 2 April 4, 1939- J. J. ALLISON ET AL 4 MACHINE FOR LEVELING LAND AND FORMING BORDERS 5 Sheets-Sheet 5 Filed April 20, 1938 1 dawn/1440.504 s/ewzvffaa/z Z2 WW Patented Apr. 4, 1939 UNITED STATES- PATENT OFFICE MACHINE FOR LEVELING LAND AND FORIVHNG BORDERS John J. Allison, Chandler, and Isham F. Collier, Tempe, Ariz.

This invention relates to a machine for leveling land and forming borders and is designed primarily for use in making borders in irrigated districts for soil erosion work, cleaning feed pens and barnyards, but it is to be understood that a machine, in accordance with this invention may be employed in any connection for which it may be found applicable, and the object of the invention is to provide, in a manner as hereinafter set forth a machine of the class referred to that may be traversed over the surface to be acted on by a light, as well as a heavy tractor and being so arranged whereby its operation will be under the control of the driver of the tractor with no extra assistance.

A further object of the invention is to provide, in a manner as hereinafter set forth a machine of the class referred to including a double edge scraper element and means disposed adjacent the ends of said element for releasably latching the edges of the latter successively in scraping position.

A further object of the invention is to provide, in a manner as hereinafter set forth, a machine including an intermittently revoluble scraper element having a pair of oppositely disposed scraper -members for successively acting to perform a scraping function, a pair of normally stationary revoluble carriers for and between which said element is arranged, a set of keepers on each of the carriers, and a pair of latching devices for simultaneous association with selected keepers of said sets for selectively and releasably maintaining the scraper element in scraping and nonscraping positions.

A further object of the invention is to provide, in a manner as hereinafter set forth, a machine of the class referred to including an angularly adjustable, intermittently revoluble, releasably latched scraper element formed with a pair of successively active scraping edges and with said element functioning as a dumping means for the loads of dirt gathered thereby during the scraping action thereof Further objects of the invention are to provide, in a manner as hereby set forth, amachine for the purpose referred to which is simple in its construction, strong, durable, compact, readily assembled, thoroughly efficient in its use, conveniently controlled, automatic in its dumping action, capable of being expeditiously repaired when occasion requires and comparatively inexpensive to set up.

With the foregoing and other objects in view, the invention consists of the novel construction,

combination and arrangement of parts as will be more specifically referred to and as are illustrated in the accompanying drawings herein is shown an embodiment of the invention, but it is to be understood that changes, variations and modifications may be resorted to which fall within the. scope of the invention as claimed.

In the drawings:

Figure 1 is a top plan view of the machine,

Figure 2 is a side elevation with the machine disposed in scraping position,

Figure 3 is a fragmentary view in top plan and upon an enlarged scale of the rear portion of one side of the machine,

Figure 4 is a fragmentary view in side elevation and upon an enlarged scale of the rear portion of one side of the machine,

Figure 5 is a section on line 5-5, Figure 4,

Figure 6 is a fragmentary view in side elevation illustrating a latching member in coactive relation with respect to a keeper,

Figure 7 is a fragmentary view in side elevation and upon an enlarged scale of the intermediate portion of a side of the machine,

Figure 8 is a section on line 88, Figure '7,

Figure 9 is a detail in sectional plan,

Figure 10 is a perspective view of a keeper, and

Figure 11 is a vertical sectional view illustrating a modified form of scraper element.

The machine includes a body part I 2 of framelike form adapted to be connected at its front, by a hitch l3 to a tractor not shown. The body part [2 is of substantially triangular contour in plan having its apex at the front of the machine. The body part I2 includes a pair of oppositely disposed rearwardly extending outwardly inclined side members l4, l5 having straight parallel rear end terminal portions l6 and I1 respectively, a central member l3 having its rear end disposed forwardly of the front ends of the portions I6, I! and its front end arranged between the front ends of members l4, IS. The body part l2 includes a transversely extending rear or base member I9 arranged between the members l4, l5 in advance of and in proximity to the forward end of the said terminal portions l6 and I1, coupling plates 20 secured to the front ends of the members l4, l5, [8. To the coupling plates 20 the hitch I3 is attached. The body part l2 also includes forwardly extending oppositely disposed outwardly inclined brace members 2!, 22 extending from the member 19 to the members l4, l5 respectively. The members I 4, I5 are in the form of outwardly opening channel irons. The member I8 is formed from a pair of inwardly opening oppositely disposed channel irons (Figure 8). The members l4, I5, 3, l9 are suitably secured together preferably by welding.

The machine includes a pair of oppositely disposed revolubly mounted carriers 23, 24 of like form and each of which is formed of a horizontal annular body portion 25 and a circular head 25 integral with the inner face of and flush with the outer edge of said body portion. The head 26 is formed with a circular row of spaced openings 27 in proximity to its point of mergence with body portion 25. Anchored against the outer face of head 26, by the holdfast means 28 is a plate 29 (Figure 9) formed with a countersunk opening 35 aligning with the axis of the head 26. The countersink of opening 30 is on the inner face of plate 29. Abutting against the outer face of head 26 and extending through plate 29 is a trunnion 3| for the carrier. The trunnion is formed of two parts 32, 33 of different diameters. The part 32 of smallest diameter, is arranged in opening 39 and welded to plate 29 as at 34. The junction of parts 32, 33 provides the trunnion with a peripheral shoulder 35 which abuts the outer face of plate 29. The part 3.2 is of materially less length than part 33. Surrounding and of less length than part 33 is a sleeve 36 which abuts the outer face of. plate 29 and is welded to the latter, as at 31.. The carriers open inwardly.

oppositely disposed bearing structures 38, 39 of like form are provided for the carriers 23, 24 respectively. The structures 38, 39 are anchored to and extend rearwardly from the rear terminal portions I6, I! of the side members I4, I 5 respectively of the body part |2. Each bearing structure includes a support 4|] (Figure 9) arranged against the inner face of and extending rearwardly from a rear end terminal portion of a side member of body part l2. The support in proximity to its rear end is formed with an opening 4| through which extends an inwardly opening tubular bearing member 42 of socketlike form. The member 42 is formed of an inner part 43 and anv outer part 44 having a tapered outer end 45. The junction of the parts 43, 44 provides member 42 with a peripheral shoulder 45. The inner edge of part 43 has the inner por-- tion thereof rabbeted, as at 46 to form an internal shoulder 41. The part 44. at its outer end portion has an axial opening 48 forming a lubricant supply duct communicating with the socket 49 provided by said member 42. Secured on the outer end of opening 48 is a lubricant cup 59. The said part 44 is arranged Within and extends outwardly from opening 4|. The shoulder 45 abuts the inner face of support 40. The outer end of sleeve 36 extends into the rabbeted portion 43 and abuts shoulder 41. One side of the part 44 has a peripheral flat facet 5| against which abuts a flat stop 52 positioned againstv the outer face of and welded to support 40, as at 52 The stop 52 coacts with facet 5| to arrest turning of member 42. The trunnion 3| extends from sleeve 36 into the socket 49 formed by member 42 and has its outer end permanently spaced from the outer end or base wall of the socket. The support 45 is secured against the inner face of the rear end terminal portion of a side member of body part |2 by a plurality of spaced holdfast devices 53 and extends above and depends from such terminal portion. The heads 26 of the carriers are spaced inwardly from the inner ends of the hearing members 42. The support 40 is formed with spaced parallel ribs 52 which are arranged against the top and bottom edges of a rear terthe carriers.

minal portion of a side member of the body part |2.

The machine includes a scraper element which may be of the straight form as indicated at 54 on Figures 1, 2, 3, 4 and 5 or of compound curvature as indicated at 55, Figure 11.

The scraper element 54 includes a holder formed of an oblong straight plate 56 and a pair of oppositely disposed spaced angle-shaped reinforcements 51, 53. The width of plate 56 corresponds to the inner diameter of the body portions of the carriers. The end terminal portions of plate 55 extend into the body portions of and has the end edges thereof abut the inner faces of the heads of the carriers. The lengthwise edges of plate 56 abut the inner faces of the body portions of the carriers. The reinforcement 57 is formed of two legs 59, disposed at right angles to each other and with reference to Figure 4 the lag. 59 has its inner side merging into the inner side of the leg 60. The reinforcement 58 is formed of two legs 6|,. 62 disposed at right angles to each other and with reference to Figure 4, the leg 5i has its inner side merging into the inner side of leg 62. indicated at B3, 64 (Figure 5). The side faces of plate 56 are indicated at 65, 55. The leg 59 is secured throughout to one of the lengthwise marginal portions of the face 65 and has its outer side edge flush with the edge 53 of the plate 55. The leg BI is secured throughout to one of the lengthwise marginal portions of the face 65 and has its outer side edge flush with the edges 64 of the plate 56. The ends of the plate 55, the reinforcements 51, 58, as well as the end terminal portions of the edges 63, 64 of plate and the end terminal portions of the outer edges of the legs 59, 6| of the reinforcements 51, 53 are welded or otherwise secured to the inner faces of The element 54 also includes a pair of oppositely disposed straight scrapers B1, 68 arranged between the carriers 23, 24 and of less length than the length of plate 56. The scraper 61 has its inner part positioned against the other marginal portion of the side face 56 and has its outer part disposed in laterally extended relation with respect to the edge 53 of plate 56. The inner part of scraper 5'! is detachably connected to plate 56 and leg 59 of reinforcement 51 by spaced ho-ldfast means 69. The scraper 68 has its inner part positioned against the other marginal portion of the side face 55 of and has its outer part disposed in laterally extended relation with respect to the edge 54 of plate 56. The inner part of scraper 58 is detachably connected to plate 56 and leg 5| of reinforcement 58 by spaced holdfast means H! in the same manner as scraper member 61.

The machine includes two sets of adjustable spaced keepers, each set being adjustably connected to the outer face of a head of a carrier. As shown each set consists of four keepers. The keepers of one set are oppositely disposed with respect to the keepers of the other set. The keepers of each of the sets are of like form and disposed in spaced relation. A set of keepers is clearly shown in Figure 4 and the keepers of a set are arranged in pairs. The keepers of one pair are indicated at 1|, I2 and those of the other pair at 13, 14. Each keeper (Figure 10) consists of a base plate 15 having formed integral with its outer face a keeper member 16. The latter consists of a shank Tl formed with a nose l8 disposed at an angle to the outer end thereof. A reinforcing web 19 is integral with the outer face of The lengthwise edges of plate 53 are plate I5 and one side of shank TI. The latter at its inner end merges into the outer face of plate I5. The outer end of nose I8 is beveled as at I9 The nose I8 extends beyond the outer lengthwise edge of plate I5. The latter is of a length that when attached to a carrier head it will span three of the openings 21 and in proximiity to its end edges 8! is formed with openings 82 for registry with the two outer openings'of the three openings 2'! which it spans. The plate I5 is detachably connected to a carrier head by spaced hold- .fast means 83 coacting with the registering openings 21, 82. When the carriers are intermittently revolved for the purpose of bringing the scraper members 61, 58 successively into action, or rather to make the scraper element B active on each half revolution of the carriers, the keepers will be arranged as shown in Figure 4, that is to say the keepers II, I2 will be diametrically opposed with respect to a carrier head and the keepers 23, 74 will also be diametrically opposed with respect to a carrier head. The keepers I3, 74 will be arranged between and each will be spaced equi-distant fromv the keepers II, I2. The pair of keepers I3, 14 are employed in connection with a latching mechanism to be referred for successively and releasably retaining the scraper members in active position. The pair of keepers H, 12 are selectively employed in connection with said latching mechanism for releasably maintaining the scraper members in inactive position. The adjusting of the keepers of the set controls the angular position of the scraper element. If it be desired that the scraper element act after one complete revolution of a carrier but one keeper will be employed. When operating the scraper element twice during one revolution of the carrier the keeper II, I2 may be removed, if not the latching mechanism to be referred to will be held in unlatching position until keeper H or 72 has been cleared and then released for coaction with a keeper I3, I0. Preferably the machine will be used with a set of four keepers arranged in the manner as shown in Figure 4:, but it is to be understood that the number of keepers used in connection with the carriers, as well as the position of the keepers may be as desired. Instead of removing certain of the keepers, when desired, the keepers which are not to be used may be swung to the dotted line position Figure 4 for the purpose of clearing the latching mechanism.

The latching mechanism which coacts with keepers on the carriers and also with selected keepers of the sets of keepers to provide for the positioning of the scraper element in a manner as referred to is generally indicated at 8 and is mounted on the body part I2 of the machine. The mechanism 84 is normally held in latching position by a spring controlled shifting or operating mechanism to be referred to, includes a pair of oppositely disposed supporting plates 85, 06 which are mounted on the side members It, I5 and extend upon the rear end terminal portions I6, I! to a point spaced from the forward ends of the supports 50, a pair of upstanding brackets or supports 8?, 33 mounted on the plates 05, 8t respectively, holdfast means 89 for securing side members I l, I5, plates 85, 86 and brackets 81, 88 together, holdfast means 9 for securing plates 05, 06 and brackets 8?, 88 together, a pair of upstanding latching members BI, 02, oppositely disposed adjustable pivotal suspensions 93, 94 for the latching members 0|, 92 respectively, upstanding crank arms 95, 96 for the shifting of the suspensions 93, 94 respectively and a rock shaft 91 common to the said crank arms.

The brackets 81, 88 are of like form and each of which consists of a base 98 formed centrally of its upper face with an upstanding arm 99 formed of a rearwardly directed part I00 and a forwardly extending upwardly inclined part I III The part I00 extends rearwardly beyond the base 98 and a plate and is disposed on its lower lengthwise edge. 7

Each latching member consists of a single strap-like body of metallic material of the desired length and width and shaped in a manner to form the latching member with an upstanding somewhat elongated skeleton body part I02 having a squared lower closed end I03 and a closed tapered upper end I 04, and a hanger part I05 merging at its lower end into the upper end of body part I02 and formed near its upper end with an opening IS. The sides of body part I02 are formed substantially centrally thereof with aligned openings I01.

The suspensions 93, 94 are of like form and each includes a slidably adjustable rectangular block I08 disposed at right angles to the inner side of hanger part I05 of a latching member. The block IE8 is formed with a threaded opening I09 (Figure 3) and a pivot H0 (Figure 5) extending from the outer end thereof and passing through opening I06 of the hanger part I05 of a latching member. Each suspension includes a combined adjusting and coupling bar III for the block I08. The bar III has threaded engagement with the wall of opening I00. After block I00 has been adjusted on bar I! I, it is retained in its adjusted position by the locknuts H2 engaging bar III. The latter has its rear terminal portion threaded as at M3 for engagement with the wall of opening I09 and the nuts H2. The forward end terminal portion of bar III is angularly disposed as at I 'I A and extends through an opening I I5 formed in and near the upper end of a crank arm or 90. Cotters I I6 are employed for connecting the bars 4 II to the crank arms 95, 96. The pivots H0 carried by the blocks I08 are connected to the hanger parts I05 of the latching members by cotters- I I0. The parts I00 of the brackets 81, 88 extend into the body parts I02 of the latching members and are provided with openings I I! (Figure 5) which align with the openings I01 and in the said sides of the said body I02. Extending through the aligned openings I01, II! are headed pivots H8 for the latching members. Cotters H9 are employed for connecting pivots H8 to the latching members. The parts IOI of the brackets 81, 58 act as combined bearings and, supports for the rock shaft 91. Spacing collars I I9 for the parts I00 of the arms 91 are carried by the pivots H8. The closed bottoms of the latching members, whenv the mechanism 84 is shifted to latching position, coacts with the noses I8 of a pair of selected keepers on the carriers for the purpose of arresting the revolving movement of the carriers after these latter have been released to permit of the scraper element dumping and moving to active position, or in other words, after the carriers have been released and they revolve in the direction of the draft of the machine, the latching mechanism is shifted in a direction to position the closed bottoms of the latching members in. the

path of the aforesaid noses It to engage them whereby further revolving of the carriers and scraper element will be arrested. The adjustment of the blocks I08 provide for increasing or decreasing the extent of the engagement of the latching members with the noses of the selected keepers to provide for a quick or a retarded release or engagement of the latching members with the noses of the selected keepers. The latching members are shifted in unison in a direction to engage or from engagement with the noses by the shifting or operating mechanism for the latching mechanism. The operating mechanism is under control of the driver of the tractor.

The operating mechanism is generally indicated at H9", is spring controlled and includes a pull member H3 of a length to permit of the driver of the tractor conveniently handling it when desired. The mechanism l It includes an upstanding lever I mounted intermediate its ends on a pivot I20 carried by and arranged near the upper end of a vertically disposed supporting structure I2I of frame-like form. The lever I 29 depends into the structure I2I and its normal position is as shown in Figure 4. The structure I2I is secured to the sides of the central member I8 of the body part I3 of the machine. Oppositely disposed brace members I22 are provided for the structure I2I. Secured upon the said central member I8 and arranged within and extending forwardly and rearwardly with respect to structure I 2| is a pair of spaced parallel plates I23 disposed on their lower lengthwise edges. The plates I23 are secured to: the structure I2I and to the member I8 and have connected thereto in proximity to their upper rear corners a stop bar I24 extending across and spaced from the upper face of member I8. Pivotally connected to the lever I20, below the top of structure I2I as at I25 are the forward ends of a pair of parallel actuating links I26 for a crank arm I21 fixed to the rock shaft 91. The rear ends of the links I21 are pivotally connected to the upper end of crank arm I2I, as at I28. Attached to the lower portion of lever I20 as at I29 is the rear ends of a forwardly extending controlling spring I30 therefor; The spring I30 has its forward end attached to the rear end of an adjustable tensioning bar I3I therefor. The bar I3I is slidably mounted in a support I32 secured upon the top of member I8 and carries an adjusting and stop nut I33. The latter provides means in connection with the bar I3I for adjusting the tension of spring I30. The stop bar I24 acts to limit the extent of the lever I20 when the latter is shifted in a direction to move the latching members to release the selected keepers with which they engage.

It will be assumed that the latching members are engaged with the keepers on the carriers 23, 24 whereby scraper member 58 is active. Now if it be desired to dump the dirt gathered by the scraper member 58, the pull member H9 is pulled forwardly to shift mechanism II9 to an extent to release the latching members from engagement with the keepers I3 which allows for the carriers and scraper element to revolve in the direction of the draft of the machine whereby the dirt will be dumped. When pull member I I9 is pulled forwardly lever I20 and the latching members will be moved to the position shown in Figure '7 and stop I24 will arrest further shifting. The mechanisms 84, H9 are held in the position (Figure '7) until keepers II pass below the latching members, after which pull member IIS is released and the operation of spring I30 will be such to restore lever I20 and the latching members to the position shown in Figure 4. The latching members will then be arranged in the path of the keepers I4 and latch the carriers and scraper element whereby the scraper member 61 will be disposed and latched in active position, similar to the position in which scraper member 68 was arranged in' before the forward pull of pull member H9". Now it will be assumed that the machine will be in the position shown in Figure 4 and it is desired to hold the scraper element in inactive position, the latching members are moved from engagement with the keepers i3 and then instantly returned to be in the path of the keepers I I, and when these latter are engaged with the latching members the scraper element will be latched in a'position at right angles to the showing thereof in Figure 4 whereby both scraper members will be releasably held in inactive position.

The modified form shown by Figure 11 will be the same as the form illustrated by Figures 1 to 10, with this exception the scraper element 55 will be of curved form. The holder I35 of element 534 will be of compound curvature, the reinforcements I33, I31 oppositely disposed and of curved contour in transverse cross section and the scraper members I38, I39 oppositely disposed and of curved contour in transverse cross section. The curvature of the legs I40 of the reinforcement, the curvature of the inner parts I4I of the scraper members I33, I39 will conform to the marginal portions of the side faces of the holder I35. Otherwise than as stated the construction of the modified form I M (Figure 11) will be the same as the other form disclosed.

What we claim is:

i. In a mobile machine of that type including a body part and a controllable revoluble scraping and dumping structure carried by and spaced from said body part, said machine comprising a pair of sets of spaced keepers adapted for connection to, selectively adjustable relative toand disposed in laterally extended relation with respect to the ends of said structure, a pair of spaced upstanding parallel oppositely shiftable latching members disposed in the path of and for coaction with selected keepers for selectively controlling intermittent successive complete revolutions and intermittent successive part revolutions of said structure to provide for alternate successive scraping and dumping actions of the latter, upstanding supports adapted to be secured to said body part, said supports extending into and having means at the rear thereof for pivotally supporting said members intermediate the ends of the latter, and spring controlled shifting means common to said members adapted to be carried by said body part, said spring controlled means being journaled in the front of said supports and pivotally connected to the upper ends of said members.

2. A mobile machine for the purpose referred to comprising a revolubly supported combined scraping and dumping structure having each of its ends formed with a circular row of spaced openings, a set of spaced selectable keepers positioned against the outer surface of each of said ends, means coacting with the keepers and said openings for adjustably connecting the keepers to the ends of said structure, each of said keepers including a shank disposed in angular relation with respect to said structure and a nose extending at an angle to the shank, a pair of spaced upstanding parallel oppositely shiftable latching members having skeleton portions disposed in the path of said noses for coaction with selected keepers for selectively controlling intermittent successive complete revolutions and intermittent successive part revolutions of said structure to provide for alternate successive scraping and dumping actions of the latter, fixed supports extended into said portions for pivotally supporting said members intermediate the ends of the latter, and spring controlled means for shifting said members in unison, said spring controlled means being journaled in the said supports and pivotally connected to the upper ends of said members.

3. In a mobile machine of that type including a body part and a controllable revoluble scraping and dumpingstructure carried by and spaced from said body part; a pair of sets of spaced keepers adapted for connection to, selectively adjustable relative to and disposed in laterally extended relation with respect to the ends of said structure, a pair of spaced upstanding parallel oppositely shiftable latching members disposed in the path of and for coaction with selected keepers for selectively controlling intermittent successive complete revolutions and intermittent successive part revolutions of said structure to provide for alternate successive scraping and dumping actions of the latter, upstanding supports adapted to be secured to said body part, said supports extending into and having means at the rear thereof for pivotally supporting said members intermediate the ends of the latter, and spring controlled shifting means common to and for operating said members in unison, said shifting means adapted to be carried by said body, journaled in the front of said supports and being pivotally and adjustably connected to the upper ends of said members.

4. A mobile machine for the purpose referred to comprising a revolubly supported combined scraping and dumping structure having each of its ends formed with acircular row of spaced openings, a set of spaced selectable keepers positioned against the outer surface of each of said ends, means coacting with the keepers and said openings for adjustably connecting the keepers to the ends of said structure, each of said keepers including a shank disposed in angular relation with respect to said structure and a nose extending at an angle to the shank, a pair of spaced upstanding parallel shiftable latching members having skeleton portions disposed in the path of said noses for coaction with selected keepers for selectively controlling intermittent successive complete revolutions and intermittent successive part revolutions of said structure to provide for alternate successive scraping and dumping actions of the latter, fixed supports extended into said portions for pivotally supporting said members intermediate the ends of the latter, and spring controlled means for shifting said members in unison, said spring controlled means being journaled in the said supports and being pivotally and adjustably connected to the upper ends of said members.

5. In a mobile machine for levelling land and forming borders and of that type including a revoluble combined scraping and dumping structure provided at its ends with spaced selectable keepers, the combination of a pair of spaced parallel upstanding oppositely shiftable latching members having portions disposed into the path of and for coacting with selected keepers for selectively controlling intermittent successive complete revolutions and intermittent successive part revolutions of said structure to provide for alternate successive scraping and dumping actions of the latter, upstanding supports having their ends positioned in said latching members above said portions, means extending through the rear ends of said supports and the latching members above said portions for pivotally supporting said members intermediate their ends, and spring controlled means common to said members for shifting them in unison, said means including a rock shaft journaled in said supports and parts extended from the shaft for pivotally and adjustab-ly connecting the upper ends of the members to said means.

6. In a mobile machine for the purpose set forth, a revoluble combined scraping and dumping structure, a set of spaced adjustable plates positioned against the outer surface of and disposed in angular relation with respect to the axis of each end of said structure, means coacting with each plate and an end of said structure to provide a pair of spaced connections for each plate for detachably securing the latter in its adjusted position to said structure, a laterally extending shank integral with and disposed diagonally with respect to the outer face of each plate, each of said shanks being formed at its outer end with a nose disposed at an angle to and projecting beyond an edge of the plate, the angle of said nose with respect to said edge being different from that of the angle of the plate with respect to said axis, a pair of spaced upstanding 'shiftable elements pivotally supported intermediate their ends and having their lower ends coacting with selected noses for controlling the revolving and scraping actions of said structure, and spring controlled means operating said elements in unison for shifting the lower ends of the elements towards and from coaction relation with the selected noses, said spring controlled means being arranged forwardly of said structure and having substantially horizontally disposed pivoted elevated rear parts pivotally connected to the upper ends of said elements.

JOHN J. ALLISON. ISHAM F. COLLIER. 

